1 | /* |
2 | * Copyright 2015 Google Inc. |
3 | * |
4 | * Use of this source code is governed by a BSD-style license that can be |
5 | * found in the LICENSE file. |
6 | */ |
7 | |
8 | #ifndef SkRSXform_DEFINED |
9 | #define SkRSXform_DEFINED |
10 | |
11 | #include "include/core/SkPoint.h" |
12 | #include "include/core/SkSize.h" |
13 | |
14 | /** |
15 | * A compressed form of a rotation+scale matrix. |
16 | * |
17 | * [ fSCos -fSSin fTx ] |
18 | * [ fSSin fSCos fTy ] |
19 | * [ 0 0 1 ] |
20 | */ |
21 | struct SkRSXform { |
22 | static SkRSXform Make(SkScalar scos, SkScalar ssin, SkScalar tx, SkScalar ty) { |
23 | SkRSXform xform = { scos, ssin, tx, ty }; |
24 | return xform; |
25 | } |
26 | |
27 | /* |
28 | * Initialize a new xform based on the scale, rotation (in radians), final tx,ty location |
29 | * and anchor-point ax,ay within the src quad. |
30 | * |
31 | * Note: the anchor point is not normalized (e.g. 0...1) but is in pixels of the src image. |
32 | */ |
33 | static SkRSXform MakeFromRadians(SkScalar scale, SkScalar radians, SkScalar tx, SkScalar ty, |
34 | SkScalar ax, SkScalar ay) { |
35 | const SkScalar s = SkScalarSin(radians) * scale; |
36 | const SkScalar c = SkScalarCos(radians) * scale; |
37 | return Make(c, s, tx + -c * ax + s * ay, ty + -s * ax - c * ay); |
38 | } |
39 | |
40 | SkScalar fSCos; |
41 | SkScalar fSSin; |
42 | SkScalar fTx; |
43 | SkScalar fTy; |
44 | |
45 | bool rectStaysRect() const { |
46 | return 0 == fSCos || 0 == fSSin; |
47 | } |
48 | |
49 | void setIdentity() { |
50 | fSCos = 1; |
51 | fSSin = fTx = fTy = 0; |
52 | } |
53 | |
54 | void set(SkScalar scos, SkScalar ssin, SkScalar tx, SkScalar ty) { |
55 | fSCos = scos; |
56 | fSSin = ssin; |
57 | fTx = tx; |
58 | fTy = ty; |
59 | } |
60 | |
61 | void toQuad(SkScalar width, SkScalar height, SkPoint quad[4]) const; |
62 | void toQuad(const SkSize& size, SkPoint quad[4]) const { |
63 | this->toQuad(size.width(), size.height(), quad); |
64 | } |
65 | void toTriStrip(SkScalar width, SkScalar height, SkPoint strip[4]) const; |
66 | }; |
67 | |
68 | #endif |
69 | |
70 | |